Contradiction
From Conservapedia
A contradiction is the simultaneous acceptance and denial of a proposition or statement. "It was the best of times and the worst of times" is a, poetic, example: the contradiction being used to enhance the poetic nature of the piece.
In a proof, if two contradictory inferences can be drawn from the premise, this indicates either that a premise is false or that the argument is invalid.
It is often held that from a contradiction anything can be inferred. This can be demonstrated:
- Take any contradiction, “A” and “Not A”, and take it to be true.
- Take anything that you want to prove, “P”
- Now because “A and Not A” is true, “A” is true, by virtue of the simplification rule.
- “A or P” is true just so long as not both A and P are false.
- So, As “A” is true, “A or P” must be true.
- If “A or P” is true, then one of “A” or “P” must be true.
- As “Not A” is true then “A” is false which means that the remaining term in “A or P” must be true.
- “P”, absolutely anything you like, is true.
